Hemostatic sponge

ABSTRACT

The present invention provides a hemostatic composite sponge comprising a porous matrix of a biomaterial and a material enhancing the adherence of said sponge to the applied tissue stably associated with at least one surface of said sponge, a method of producing these sponges and their use in hemostasis.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/970,203, filed Dec. 16, 1010, which is a nonprovisional of, andclaims the benefit of priority to, U.S. Provisional Application No.61/287,088, filed Dec. 16, 2009, the entire contents of which isincorporated herein by reference for all purposes.

FIELD OF THE INVENTION

The present invention relates to the field of hemostatic sponges, amethod of producing said sponges and their uses in hemostasis.

BACKGROUND OF THE INVENTION

Biological glues based on coagulation factors of human or animal originhave long been known. A method for producing tissue adhesives based onfibrinogen and factor XIII has been described in U.S. Pat. No.4,362,567, U.S. Pat. No. 4,298,598 and U.S. Pat. No. 4,377,572. Thetissue adhesives are usually applied together with a separate componentcontaining thrombin, which is enzymatically acting on fibrinogen to formfibrin, and on factor XIII to form the active factor XIIIa, whichcross-links the fibrin to obtain a stable fibrin clot.

Collagen pads have been used for many years to improve wound healing orto stop bleeding. Their mechanism of action in hemostasis is based onplatelet aggregation and activation, the formation of thrombin on thesurface of activated platelets and the formation of a hemostatic fibrinclot by the catalytic action of thrombin on fibrinogen. To improve thehemostatic action of collagen pads or sheets it has been suggested toinclude factors of hemostasis within such pads.

In U.S. Pat. No. 4,600,574 a tissue adhesive based on collagen combinedwith fibrinogen and factor XIII is described. This material is providedin the lyophilized form, ready for use. The fibrinogen and factor XIIIare combined with the collagen by impregnating the collagenous flatmaterial with a solution comprising fibrinogen and factor XIII, andlyophilizing said material.

The WO 97/37694 discloses a hemostatic sponge based on collagen and anactivator or proactivator of blood coagulation homogeneously distributedtherein. This sponge is provided in a dry form, which could be air-driedor lyophilized. However, it still contains a water content of at least2%.

U.S. Pat. No. 5,614,587 discusses bioadhesive compositions comprisingcross-linked collagen using a multifunctionally activated synthetichydrophilic polymer, as well as methods of using such compositions toeffect adhesion between a first surface and a second surface, wherein atleast one of the first and second surfaces can be a native tissuesurface.

Collagen-containing compositions which have been mechanically disruptedto alter their physical properties are described in U.S. Pat. No.5,428,024, U.S. Pat. No. 5,352,715, and U.S. Pat. No. 5,204,382. Thesepatents generally relate to fibrillar and insoluble collagens. Aninjectable collagen composition is described in U.S. Pat. No. 4,803,075.An injectable bone/cartilage composition is described in U.S. Pat. No.5,516,532. A collagen-based delivery matrix comprising dry particles inthe size range from 5 μm to 850 μm which may be suspended in water andwhich has a particular surface charge density is described in WO96/39159. A collagen preparation having a particle size from 1 μm to 50μm useful as an aerosol spray to form a wound dressing is described inU.S. Pat. No. 5,196,185. Other patents describing collagen compositionsinclude U.S. Pat. No. 5,672,336 and U.S. Pat. No. 5,356,614.

BRIEF SUMMARY OF THE INVENTION

The subject of the invention is a hemostatic porous composite spongecomprising a matrix of a biomaterial and a material enhancing theadherence of said sponge to the applied tissue stably associated with atleast one surface of said sponge, wherein said material is essentiallyfree of a hydrogel forming component.

It has been found that previous pads of fibrous biomaterials, inparticular collagen pads, for wound healing failed to induce hemostasisat conditions with impaired hemostasis (e.g. after heparinization). Theinventive sponge improves hemostasis.

It has further been found that if a further material is present on asurface of the biomatrix material as an active hemostatic layer such alayer tends to be instable in that the material has a tendency to detachfrom the sponge, especially during application of the sponge on thetissue and when being adjusted to the geometry of said tissue.

It has also been found that the absence of a further hydrogel formingcomponent, such as e.g. a particulate material, e.g. gelatin particles,has advantageous properties especially with regards to lower swellingproperties of the sponge as a whole.

It has been possible to overcome these drawbacks in that a sponge of thepresent invention is provided.

A further aspect relates to a method of manufacturing a hemostaticporous sponge comprising

a) providing a porous sponge of a matrix of a biomaterial,

b) providing a material enhancing the adherence of said sponge to theapplied tissue in the form of a suspension, a solution or powder,wherein said material is essentially free of a hydrogel formingcomponent,

c) contacting a) and b) so that the material of b) is stably associatedwith at least one surface of said sponge so that a hemostatic compositesponge is obtained, optionally

d) drying the composite sponge obtained in step c), optionally

e) sterilizing said composite sponge obtained in step c) or d).

Another aspect relates to a method of treating an injury comprisingadministering a hemostatic porous composite sponge to the site ofinjury.

Also provided is a kit for preparing a wound coverage, comprising asponge as herein disclosed and pharmaceutically active substances. Thiskit and its components are in particular for the manufacture of amedical sponge for the treatment of an injury.

Those skilled in the art will readily understand that all preferredembodiments disclosed in the following are examples of specificembodiments, but are not necessarily limiting the general inventiveconcept. Furthermore, all special embodiments can be read on allinventive aspects and embodiments in any combination, if not mutuallyexclusive. All equivalents or obvious alterations or modifications asrecognized by those skilled in the art are included by the presentinvention.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1 to 4 show hemostatic performances of the sponges preparedaccording to examples 1 (=FIG. 1), 4 (=FIG. 2), 5 (=FIGS. 3) and 6(=FIG. 4) in an animal model as described in Example 10.

The present invention is further exemplified by the following exampleswithout being lim-ited thereto.

The following abbreviations are used:

COH102 Pentaerythritolpoly(ethyleneglycol)ether tetrasuccinimidylglutarate

COH206 Pentaerythritolpoly(ethyleneglycol)ether tetra-thiol

EtOH ethanol

PEG polyethylene glycol

PET polyethylene terephthalate

DETAILED DESCRIPTION OF THE INVENTION

The object of the invention is a hemostatic porous composite spongecomprising a matrix of a biomaterial and a material enhancing theadherence of said sponge to the applied tissue stably associated with atleast one surface of said sponge, wherein said material is essentiallyfree of a hydrogel forming component.

“Stably associated” according to the present invention means that thematerial enhancing the adherence of said sponge to the applied tissuestays firmly associated with the sponge during application of thissponge to the tissue and adjusting to the geometry of said tissue, evenif the sponge is e.g. bended during that application.

Preferably the biomaterial is collagen, a protein, a biopolymer, or apolysaccharide. Especially preferred is a biomaterial selected from thegroup consisting of collagen, gelatin, fibrin, a polysaccharide, e.g.chitosan, and a derivative thereof, more preferred collagen andchitosan, especially preferred collagen.

The sponge is a porous network of a biomaterial able to absorb bodyfluids when applied to the site of an injury. Furthermore, the sponge isusually flexible and suitable to be applied on diverse tissues andlocations with various shapes.

The collagen used for the present invention can be from any collagensuitable to form a gel, including a material from liquid, pasty, fibrousor powdery collageneous materials that can be processed to a porous orfibrous matrix. The preparation of a collagen gel for the production ofa sponge is e.g. described in the EP 0891193 (incorporated herein byreference) and may include acidification until gel formation occurs andsubsequent pH neutralisation. To improve gel forming capabilities orsolubility the collagen may be (partially) hydrolyzed or modified, aslong as the property to form a stable sponge when dried is notdiminished.

The collagen sponge according to the present invention preferably has alower density as compared to the density of a collagen film. Preferablythe density is between about 5 to about 100 mg per cm3, whereasdensities of films are higher than about 650 mg per cm3. An especiallypreferred collagen sponge according to the present invention is the onemarketed under the name Matristypt®.

The collagen or gelatin of the sponge matrix is preferably of animalorigin, preferably bovine or equine. However, also human collagen mightbe used in case of a hypersensitivity of the patient towards xenogenicproteins. The further components of the sponge are preferably of humanorigin, which makes the sponge suitable especially for the applicationto a human.

In a preferred embodiment the matrix material of the fibrousbiocompatible polymer which forms the porous network of the spongeconstitutes of between 1-50%, 1-10%, preferably about 3% of the driedporous sponge (w/w-%).

In a preferred embodiment the material enhancing the adherence of saidsponge to the applied tissue, in the following called “the material”, isa mixture of two pre-polymers comprising a first cross-linkablecomponent and a second cross-linkable component that cross-links withthe first cross-linkable component under reaction enabling conditions ora formed polymer in association with said sponge.

The material enhancing the adherence of said sponge to the appliedtissue stably associated with at least one surface of said sponge isessentially free of a hydrogel forming component, especially free of aparticulate hydrogel forming component, e.g. gelatin particulatematerial or gelatin particles.

More preferably said first and/or second cross-linkable componentcomprise a derivative of polyethylene glycol (PEG), e.g. a derivativewhich is able to react under given conditions. Preferably one of thecross-linkable components is capable of covalently reacting with tissue.

Such materials suitable for a sponge for use as a hemostat are e.g.disclosed in the WO2008/016983 (incorporated herein by reference in itsentirety) and commercially available under the trademark CoSeal®.Preferred materials mediate adjunctive hemostasis by themselves, and canbe suitable to mechanically seal areas of leakage. Such materials arefor ex-ample bioresorbable polymers, in particular polymers thatcross-link and solidify upon exposure to body fluids. In furtherembodiments the material is resorbable and/or biocompatible and can bedegraded by a subject, in particular a human subject, in less than 6months, less than 3 months, less than 1 month or less than 2 weeks.

A special material enhancing the adherence of said sponge to the appliedtissue may comprise a first cross-linkable component, a secondcross-linkable component that cross-links with the first cross-linkablecomponent under reaction enabling conditions, wherein the first andsecond cross-linkable component cross-link to form a layer.

The first cross-linkable component can include multiple nucleophilicgroups and the sec-ond cross-linkable component can include multipleelectrophilic groups. Upon contact with a biological fluid, or in otherreaction enabling conditions, the cross-linkable first and secondcomponents cross-link to form a porous matrix having interstices.

In some aspects, the first cross-linkable component of the materialincludes a multi-nucleophilic polyalkylene oxide having m nucleophilicgroups, and the second cross-linkable component includes amulti-electrophilic polyalkylene oxide. The multi-nucleophilicpolyalkylene oxide can include two or more nucleophilic groups, forexample NH2, —SH, —H, —PH2, and/or —CO—NH—NH2. In some cases, themulti-nucleophilic polyalkylene oxide includes two or more primary aminogroups. In some cases, the multi-nucleophilic polyalkylene oxideincludes two or more thiol groups. The multi-nucleophilic polyalkyleneoxide can be polyethylene glycol or a derivative thereof. In some cases,the polyethylene glycol includes two or more nucleophilic groups, whichmay include a primary amino group and/or a thiol group. Themulti-electrophilic polyalkylene oxide can include two or moreelectrophilic groups such as CO2N(COCH2)2, —CO2H, —CHO, —CHOCH2, —N═C═O,—SO2CH═CH2, N(COCH) 2, and/or —S—S—(C5H4N). The multi-electrophilicpolyalkylene oxide may include two or more succinimidyl groups. Themulti-electrophilic polyalkylene oxide may include two or moremaleimidyl groups.

In some cases, the multi-electrophilic polyalkylene oxide can be apolyethylene glycol or a derivative thereof

In special embodiments the first and/or second cross-linkable componentis/are synthetic polymers, preferably comprising PEG. The polymer can bea derivative of PEG comprising active side groups suitable forcross-linking and adherence to a tissue. Preferably, the adhesivecomprises succinimidyl, maleimidyl and/or thiol groups. In a two polymerset-up, one polymer may have succinyl or maleimidyl groups and a secondpolymer may have thiol or amino groups which can attach to the groups ofthe first polymer. These or additional groups of the adhesive mayfacilitate the adherence to a tissue.

Preferably the material enhancing the adherence of said sponge to theapplied tissue, such as modified PEG materials as mentioned before, ispresent in a range of 5 to 50 mg/cm2 of the biomaterial, preferably 10to 20 mg/cm2 of the biomaterial, e.g. collagen.

The sponge as a whole is biodegradable, being suitable for biologicaldecomposition in vivo, or bioresorbable, i.e. able to be resorbed invivo. Full resorption means that no significant extracellular fragmentsremain. A biodegradable material differs from a non-biodegradablematerial in that a biodegradable material can be biologically decomposedinto units which may either be removed from the biological system and/orchemically incorporated into the biological system. In a preferredembodiment the particular material, the matrix material or sponge as awhole can be degraded by a subject, in particular a human subject, inless than 6 month, less than 3 month, less than 1 month, less than 2weeks.

In a preferred embodiment the sponge has the material enhancing theadherence of said sponge to the applied tissue in the form of acontinuous or discontinuous layer on at least one surface of saidsponge.

The sponge of the present invention preferably has an overall thicknessof less than 2.5 mm, more preferred about 1 mm to about 2.5 mm.

The sponge of the present invention is preferably used in minimalinvasive surgery, e.g. for laparoscopic application.

The sponge may be dried and after drying, the sponge may have a watercontent of at least 0.5 (percentages given in w/w here). In certainembodiments the sponge can be freeze-dried or air-dried.

The sponge may further comprise an activator or proactivator of bloodcoagulation, including fibrinogen, thrombin or a thrombin precursor, ase.g. disclosed in U.S. Pat. No. 5,714,370 (incorporated herein byreference). Thrombin or the precursor of thrombin is understood as aprotein that has thrombin activity and that induces thrombin activitywhen it is contacted with blood or after application to the patient,respectively. Its activity is expressed as thrombin activity (NIH-Unit)or thrombin equivalent activity developing the corresponding NIH-Unit.The activity in the sponge can be 100-10.000, preferably 500-5.000. Inthe following thrombin activity is understood to comprise both, theactivity of thrombin or any equivalent activity. A protein with thrombinactivity might be selected from the group consisting of alpha-thrombin,meizothrombin, a thrombin derivative or a recombinant thrombin. Asuitable precursor is possibly selected from the group consisting of:prothrombin, factor Xa optionally together with phospholipids, factorIXa, activated prothrombin complex, FEIBA, any activator or aproactivator of the intrinsic or extrinsic coagulation, or mixturesthereof.

The hemostatic sponge according to the invention might be used togetherwith further physiologic substances. For example, the sponge preferablyfurther comprises pharmacologically active substances, among themantifibrinolytics, such as a plasminogenactivator-inhibitor or a plasmininhibitor or an inactivator of fibrinolytics. A preferredantifibrinolytic is selected from the group consisting of aprotinin oran aprotinin derivative, alpha2-macroglobulin, an inhibitor orinactivator of protein C or activated protein C, a substrate mimicbinding to plasmin that acts competitively with natural substrates, andan antibody inhibiting fibrinolytic activity.

As a further pharmacologically active substance an antibiotic, such asan antibacterial or antimycotic might be used together with the spongeaccording to the invention, preferably as a component homogeneouslydistributed in the sponge. Further bioactive substances such as growthfactors and/or pain killers may be also present in the inventive sponge.Such a sponge might be useful in e.g. wound healing.

Further combinations are preferred with specific enzymes or enzymeinhibitors, which may regulate, i.e. accelerate or inhibit, theresorption of the sponge. Among those are collagenase, its enhancers orinhibitors. Also, a suitable preservative may be used together with thesponge or may be contained in the sponge.

Although a preferred embodiment relates to the use of the hemostaticsponge which contains the activator or proactivator of blood coagulationas the only active component, further substances that influence thevelocity of blood coagulation, hemostasis and quality of the sealing,such as tensile strength, inner (adhesive) strength and durability mightbe comprised.

Procoagulants that enhance or improve the intrinsic or extrinsiccoagulation, such as factors or cofactors of blood coagulation, factorXIII, tissue factor, prothrombin complex, activated prothrombin complex,or parts of the complexes, a prothrombinase complex, phospholipids andcalcium ions, might be used. In case of a surgical procedure where aprecise sealing is needed, it might be preferable to prolong the workingperiod after the hemostatic sponge is applied to the patient and beforeclotting is affected. The prolongation of the clotting reaction will beensured, if the sponge according to the invention further comprisesinhibitors of blood coagulation in appropriate amounts. Inhibitors, suchas antithrombin III optionally together with heparin, or any otherserine protease inhibitor, are preferred.

It is also preferred to have such additives, in particular the thrombinor a precursor of thrombin evenly distributed in the material in orderto prevent local instability or hypercoagulabil-ity of the material.Even with a certain water content the thrombin activity is surprisinglystable, probably because of the intimate contact of thrombin andcollagen in the homogeneous mixture. Nevertheless, thrombin stabilizerspreferably selected from the group consisting of a polyol, apolysaccharide, a polyalkylene glycol, amino acids or mixtures thereofmight be used according to the invention. The exemplary use of sorbitol,glycerol, polyethylene glycol, polypropylene glycol, mono- ordisaccharides such as glucose or saccharose or any sugar or sulfonatedamino acid capable of stabilizing thrombin activity is preferred.

In another embodiment a biocompatible, resorbable hydrogel capable ofabsorbing liquid is contained within the sponge of the presentinvention.

The present invention also provides a wound coverage comprising a spongeaccording to the invention. The sponge and all additional layers can beprovided in a ready to use wound coverage in suitable dimensions. Thesponge and/or the coverage can be a pad or a sheet, preferably having athickness of at least 3 mm or at least 5 mm and/or up to 20 mm,depending on the indication. When the relatively thick flexible spongeis applied to a wound it is important that blood and fibrinogen can beabsorbed throughout the sponge before fibrin is formed that might act asa barrier for the absorption of further wound secret.

Another aspect of the invention relates to a method of manufacturing ahemostatic porous sponge comprising

a) providing a sponge comprising a matrix of a biomaterial,

b) providing a material enhancing the adherence of said sponge to theapplied tissue in the form of a suspension, a solution or powder,

c) contacting a) and b) so that the material of b) is present on atleast one surface of said sponge, and optionally

d) drying the sponge obtained in step c).

Drying may include freeze drying or air drying and comprises removingvolatile components of the fluid.

In a further aspect the present invention provides a hemostatic poroussponge obtainable by the method according to the invention describedabove. All preferred embodiments mentioned above for a hemostatic spongecan also be read to this obtainable sponge.

The present invention also provides a method of treating an injurycomprising administering a hemostatic porous composite sponge comprisinga matrix of a biomaterial and a material enhancing the adherence of saidsponge to the applied tissue. The injury may comprise a wound, ahemorrhage, damaged tissue and/or bleeding tissue.

EXAMPLES Example 1 Collagen Sponges Treated With Acidic Solution of TwoReactive PEGs

Aqueous, acidic solutions (pH 3.0, HCl) of COH102 and COH206 withPEG-concentrations (COH102 and COH206 1:1) of 10 mg/cm³, 35 mg/cm³, 70mg/cm³ and 100 mg/cm³ are prepared and filled into 9×7 cm PET-trays.Commercial available bovine collagen sponges (Matristypt®), 9×7 cm, withthe same volume as the previously filled PEG-solution are placed on thetop of the solutions. After absorption of the PEG-solution, the collagenmaterials are lyophilized.

After lyophilization the dried sponges may be packed together withdesiccants in water vapor impermeable pouches and may be furthergamma-sterilized, e.g. with 25 kGray.

Example 2 Collagen Sponges Treated With EtOH-Solution of Two ReactivePEGs

COH102 and COH206 are dissolved in completely dried EtOH.PEG-concentrations (COH102 and COH206 1:1) of 10 mg/cm³, 35 mg/cm³, 70mg/cm³ and 100 mg/cm³ are prepared and the solutions are filled into 9×7cm PET-trays. Commercial available bovine collagen sponges(Matristypt®), 9×7 cm, with the same volume as the previously filledPEG-solution are placed on the top of the solutions. After absorption ofthe PEG-solution the collagen materials are dried in a vacuum chamber.

Dried sponges may be packed together with desiccants in water vaporimpermeable pouches and may be gamma-sterilized, e.g. with 25 kGray.

Example 3 Preparation of Collagen-/Reactive PEG Constructs

22 ml of aqueous, acidic solutions (pH 3.0, HCl) containing variousconcentrations (2.15 mg/cm³, 4.3 mg/cm³ and 7.2 mg/cm³) of bovine coriumcollagen and PEG (COH102 and COH206 1:1)-concentrations of 7.2 mg/cm³,14.3 mg/cm³, 28.6 mg/cm³and 57.3 mg/cm³ are prepared, filled intoPET-trays and lyophilized.

The dried sponges may be packed together with desiccants in water vaporimpermeable pouches and may be gamma-sterilized, e.g. with 25 kGray.

Example 4 Preparation of Two Layer Collagen-/Reactive PEG Constructs

11 ml and 22 ml of acidic collagen-/PEG-solutions (pH 3.0, HCl) asdescribed in example 3 are filled into PET-trays and immediately frozenat −20° C. On the top of the ice phase 11 ml or 22 ml of a 1% bovinecorium collagen solution, pH 3.0 (HCl) are applied and the constructsobtained are freeze-dried.

The dried sponges may be packed together with desiccants in water vaporimpermeable pouches and may be gamma-sterilized, e.g. with 25 kGray.

Example 5 Homogeneous Coating of Collagen Sponges With Reactive PEGs

A 1:1 powder mixture of COH102 and COH206 is homogeneously distributedonto one surface of a commercially available collagen sponge or on asponge prepared after one of the methods as described in example 1, 2, 3and 4. PEG-amounts of 2 mg/cm², 7 mg/cm², 10 mg/cm², 14 mg/cm² and 20mg/cm² are used for the coating. The PEG-powder mixture is fixed on thesurface of the sponge, e.g. by melting, such as by placing the spongeswith the PEG-powder mixture into a preheated oven at 60 to 65° C. for 4minutes.

The dried sponges may be packed together with desiccants in water vaporimpermeable pouches and may be gamma-sterilized, e.g. with 25 kGray.

Example 6 Discontinuous Coating of Collagen Sponges With Reactive PEGs

Pads are prepared as described in example 5 with the exception thatbefore coating a grid is placed onto the surface of the collagen sponge,so that the surface of the pad is partially shielded and partially notcovered by the PEG powder. Grid matrices with a mesh size of 5 mm and 10mm are used and removed after powder distribution. Fixation of thepowder, packaging and sterilization are those as described in example 5.

These prototypes allow a better penetration of the blood into thecollagen pad, where coagulation occurs due to the procoagulant activityof collagen. The reactive PEGs assure the adhesion of the pad to thewound surface.

Example 7 Preparation of Constructs of Collagen With Cross-Linked PEG

a) Onto a bovine collagen sponge the reactive PEGs COH102 and COH206(1:1) are sprayed with a commercial available spray applicator composedof a double syringe and a gas driven spray head (Duplospray, Baxter).One syringe contains COH102 and COH206 at pH 3.0 and the second syringebuffer, pH 9.4. The polymerization of the two PEG-components occurrs onthe surface of collagen immediately after deposition. The sponge may bedried in a vacuum chamber.

b) A collagen sponge is treated with an acidic PEG-solution as describedin example 1. In order to start the cross-linking between the twoPEG-components and the collagen matrix, the wet sponge is treated with abasic buffer system and may be lyophilized afterwards.

Example 8 Continuous Coating of a Chitosan-/Gelatin Sponge With ReactivePEG's

A 1:1 powder mixture of COH102 and COH206 is homogeneously distributedonto one surface of a commercially available chitosan-/gelatin(Chitoskin®, Beese Medical) sponge. A PEG-amount of 14 mg/cm² is usedfor the coating. The PEG-powder mixture is fixed on the surface of thesponge, e.g. by melting, such as by placing the sponges with thePEG-powder mixture into a preheated oven at 60 to 65° C. for 4 minutes.

The dried sponges may be packed together with desiccants in water vaporimpermeable pouches and may be gamma-sterilized, e.g. with 25 kGray.

Example 9 Coating of a Oxidized Cellulose Fabric With Reactive PEG's

A 1:1 powder mixture of COH102 and COH206 is homogeneously distributedonto one surface of a commercially available oxidized cellulose fabric(Traumstem®, Bioster). A PEG-amount of 14 mg/cm² is used for thecoating. The PEG-powder mixture is fixed on the surface of the sponge,e.g. by melting, such as by placing the sponges with the PEG-powdermixture into a preheated oven at 60 to 65° C. for 4 minutes.

The dried sponges may be packed together with desiccants in water vaporimpermeable pouches and may be gamma-sterilized, e.g. with 25 kGray.

Example 10 Preclinical Applications

A sponge as prepared according to the examples is tested in heparinizedpigs (1.5-fold ACT) in a liver abrasion model. With a rotating grindingmachine a circular bleeding wound with a diameter of 1.8 cm is createdon the surface of a liver lobe. A 3x3 cm sponge is applied andmoderately pressed against the wound for 2 minutes with a piece of gauzesoaked with saline buffer. After removal of the gauze a good hemostaticperformance is achieved as shown in FIGS. 1 to 4.

1. A hemostatic composite sponge comprising a porous sponge of a matrixof a biomaterial and a material enhancing the adherence of said spongeto the applied tissue stably associated with at least one surface ofsaid sponge, wherein said material is essentially free of a hydrogelforming component.
 2. The sponge according to claim 1, wherein saidbiomaterial is selected from the group consisting of collagen, gelatin,fibrin, a polysaccharide, and a derivative thereof.
 3. The spongeaccording to claim 1, wherein said material enhancing the adherence ofsaid sponge to the applied tissue is a mixture of two prepolymerscomprising a first cross-linkable component and a second cross-linkablecomponent that cross-links with the first cross-linkable component underreaction enabling conditions or a pre-formed polymer.
 4. The spongeaccording to claim 1, wherein said first and/or second cross-linkablecomponent comprise a derivative of polyethylene glycol.
 5. The spongeaccording to claim 1, wherein said material enhancing the adherence ofsaid sponge to the applied tissue forms a continuous or discontinuouslayer on at least one surface of said sponge.
 6. The sponge according toclaim 1 having an overall thickness of about 1 mm to about 2.5 mm. 7.The sponge according to claim 1 use in minimal invasive surgery.
 8. Thesponge according to claim 1 wherein the material enhancing the adherenceof said sponge to the applied tissue is present in a concentration of 5to 500 mg per cm² of biomaterial.
 9. A method of manufacturing ahemostatic composite sponge comprising providing a porous sponge of amatrix of a biomaterial; providing a material enhancing the adherence ofsaid sponge to the applied tissue in the form of a suspension, asolution or powder, wherein said material is essentially free of ahydrogel forming component; and contacting the sponge and the materialso that the material is stably associated with at least one surface ofsaid sponge so that a hemostatic composite sponge is obtained. 10.Method of treating a wound, a hemorrhage, damaged tissue and/or bleedingtissue comprising administering a hemostatic composite sponge ofclaim
 1. 11. The sponge according to claim 2, wherein the polysaccharidecomprises chitosan.
 12. The sponge according to claim 2, wherein saidmaterial enhancing the adherence of said sponge to the applied tissue isa mixture of two pre-polymers comprising a first cross-linkablecomponent and a second cross-linkable component that cross-links withthe first cross-linkable component under reaction enabling conditions ora pre-formed polymer.
 13. The sponge according to claim 2, wherein saidfirst and/or second cross-linkable component comprise a derivative ofpolyethylene glycol.
 14. The sponge according to claim 3, wherein saidfirst and/or second cross-linkable component comprise a derivative ofpolyethylene glycol.
 15. The sponge according to claim 12, wherein saidfirst and/or second cross-linkable component comprise a derivative ofpolyethylene glycol.
 16. The sponge according to claim 7, wherein theminimal invasive surgery comprises a laparoscopic application.
 17. Thesponge according to claim 8, wherein the material enhancing theadherence of said sponge to the applied tissue is present in aconcentration of between 5 to 100 mg per cm².
 18. The method of claim 9,further comprising drying the composite sponge.
 19. The method of claim10, further comprising sterilizing the composite sponge.
 20. The methodof claim 9, further comprising sterilizing the composite sponge.